Mitochondrial Modulation of Ca2+-Induced Ca2+-Release in Rat Sensory Neurons

2006 ◽  
Vol 96 (3) ◽  
pp. 1093-1104 ◽  
Author(s):  
Joshua G. Jackson ◽  
Stanley A. Thayer
Keyword(s):  
Plasma Membrane ◽  
Sensory Neurons ◽  
Oscillation Frequency ◽  
Cyclopiazonic Acid ◽  
Cellular Level ◽  
Dorsal Root Ganglion Neurons ◽  
Whole Cell Patch Clamp ◽  
Carbonyl Cyanide ◽  
Synthase Inhibitor ◽  
Ganglion Neurons

Ca2+-induced Ca2+-release (CICR) from ryanodine-sensitive Ca2+ stores provides a mechanism to amplify and propagate a transient increase in intracellular calcium concentration ([Ca2+]i). A subset of rat dorsal root ganglion neurons in culture exhibited regenerative CICR when sensitized by caffeine. [Ca2+]i oscillated in the maintained presence of 5 mM caffeine and 25 mM K+. Here, CICR oscillations were used to study the complex interplay between Ca2+ regulatory mechanisms at the cellular level. Oscillations depended on Ca2+ uptake and release from the endoplasmic reticulum (ER) and Ca2+ influx across the plasma membrane because cyclopiazonic acid, ryanodine, and removal of extracellular Ca2+ terminated oscillations. Increasing caffeine concentration decreased the threshold for action potential-evoked CICR and increased oscillation frequency. Mitochondria regulated CICR by providing ATP and buffering [Ca2+]i. Treatment with the ATP synthase inhibitor, oligomycin B, decreased oscillation frequency. When ATP concentration was held constant by recording in the whole cell patch-clamp configuration, oligomycin no longer affected oscillation frequency. Aerobically derived ATP modulated CICR by regulating the rate of Ca2+ sequestration by the ER Ca2+ pump. Neither CICR threshold nor Ca2+ clearance by the plasma membrane Ca2+ pump were affected by inhibition of aerobic metabolism. Uncoupling electron transport with carbonyl cyanide p-trifluoromethoxy-phenyl-hydrazone or inhibiting mitochondrial Na+/Ca2+ exchange with CGP37157 revealed that mitochondrial buffering of [Ca2+]i slowed oscillation frequency, decreased spike amplitude, and increased spike width. These findings illustrate the interdependence of energy metabolism and Ca2+ signaling that results from the complex interaction between the mitochondrion and the ER in sensory neurons.

scholarly journals Voltage-gated Na+ currents in human dorsal root ganglion neurons

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Xiulin Zhang ◽  
Birgit T Priest ◽  
Inna Belfer ◽  
Michael S Gold
Keyword(s):  
Sensory Neurons ◽  
Tissue Injury ◽  
Dorsal Root Ganglion Neurons ◽  
Pharmacological Properties ◽  
Pain Mechanisms ◽  
Voltage Gated ◽  
Whole Cell Patch Clamp ◽  
Na Currents ◽  
Ganglion Neurons ◽  
Peripheral Sensory

Available evidence indicates voltage-gated Na+ channels (VGSCs) in peripheral sensory neurons are essential for the pain and hypersensitivity associated with tissue injury. However, our understanding of the biophysical and pharmacological properties of the channels in sensory neurons is largely based on the study of heterologous systems or rodent tissue, despite evidence that both expression systems and species differences influence these properties. Therefore, we sought to determine the extent to which the biophysical and pharmacological properties of VGSCs were comparable in rat and human sensory neurons. Whole cell patch clamp techniques were used to study Na+ currents in acutely dissociated neurons from human and rat. Our results indicate that while the two major current types, generally referred to as tetrodotoxin (TTX)-sensitive and TTX-resistant were qualitatively similar in neurons from rats and humans, there were several differences that have important implications for drug development as well as our understanding of pain mechanisms.

scholarly journals Activity and Ca2+ regulate the mobility of TRPV1 channels in the plasma membrane of sensory neurons

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Eric N Senning ◽  
Sharona E Gordon
Keyword(s):  
Plasma Membrane ◽  
Sensory Neurons ◽  
Dorsal Root ◽  
Optical Recording ◽  
Dorsal Root Ganglion Neurons ◽  
Mechanical Stimuli ◽  
Channel Activation ◽  
Trpv1 Channels ◽  
Ganglion Neurons ◽  
Ca2 Channels

TRPV1 channels are gated by a variety of thermal, chemical, and mechanical stimuli. We used optical recording of Ca2+ influx through TRPV1 to measure activity and mobility of single TRPV1 molecules in isolated dorsal root ganglion neurons and cell lines. The opening of single TRPV1 channels produced sparklets, representing localized regions of elevated Ca2+. Unlike sparklets reported for L-type Ca2+ channels, TRPV4 channels, and AchR channels, TRPV1 channels diffused laterally in the plasma membrane as they gated. Mobility was highly variable from channel-to-channel and, to a smaller extent, from cell to cell. Most surprisingly, we found that mobility decreased upon channel activation by capsaicin, but only in the presence of extracellular Ca2+. We propose that decreased mobility of open TRPV1 could act as a diffusion trap to concentrate channels in cell regions with high activity.

Modulation of Voltage-Activated Calcium Currents by Mechanical Stimulation in Rat Sensory Neurons

1998 ◽  
Vol 80 (4) ◽  
pp. 1647-1652 ◽  
Author(s):  
Yona Bouskila ◽  
Hugh Bostock
Keyword(s):  
Action Potential ◽  
Sensory Neurons ◽  
Mechanical Stimulation ◽  
Action Potential Duration ◽  
Calcium Currents ◽  
Dorsal Root Ganglion Neurons ◽  
Patch Clamp Technique ◽  
Whole Cell Patch Clamp ◽  
Low Threshold ◽  
Ganglion Neurons

Bouskila, Yona and Hugh Bostock. Modulation of voltage-activated calcium currents by mechanical stimulation in rat sensory neurons. J. Neurophysiol. 80: 1647–1652, 1998. We examined the effects of mechanical stress, induced by a stream of bath solution, on evoked action potentials, electrical excitability, and Ca2+ currents in rat dorsal root ganglion neurons in culture with the use of the whole cell patch-clamp technique. Action-potential duration was altered reversibly by flow in 39% of the 51 neurons tested, but membrane potential and excitability were unaffected. The flow-induced increases and decreases in action-potential duration were consistent with the different effects of flow on two types of Ca2+ channel, determined by voltage-clamp recordings of Ba2+ currents. Current through ω-conotoxin–sensitive (N-type) Ca2+ channels increased by an estimated 74% with flow, corresponding to 23% increase in the total high voltage–activated current, whereas current through low-threshold voltage-activated (T-type) channels decreased by 14%. We conclude that modulation of voltage-activated Ca2+ currents constitutes a route by which mechanical events can regulate Ca2+ influx in sensory neurons.

Annexin VI modulates Ca2+ and K+ conductances of spinal cord and dorsal root ganglion neurons

1996 ◽  
Vol 271 (6) ◽  
pp. C2004-C2015 ◽  
Author(s):  
J. M. Naciff ◽  
M. M. Behbehani ◽  
M. A. Kaetzel ◽  
J. R. Dedman
Keyword(s):  
Spinal Cord ◽  
Plasma Membrane ◽  
Sensory Neurons ◽  
Dorsal Root ◽  
Active Role ◽  
Dorsal Root Ganglion Neurons ◽  
Drg Neurons ◽  
Preferential Localization ◽  
Annexin Vi ◽  
Ganglion Neurons

Annexin VI is a member of a Ca(2+)-dependent phospholipid-binding protein family that participates in the transduction of the intracellular Ca2+ signal. We have identified annexin VI as one of the major annexins expressed differentially by sensory neurons of dorsal root ganglia (DRG) and by neurons of spinal cord (SC) of the rat and the mouse. This annexin shows a preferential localization at the plasma membrane of the soma and cellular processes, particularly in motoneurons of the SC. This finding suggests an active role of annexin VI in the Ca(2+)-dependent regulation of plasma membrane functions. To test this possibility, the neuronal function of annexin VI was evaluated by whole cell electrophysiology of mouse embryo SC and DRG neurons. An antibody was developed that has the property of neutralizing annexin VI-phospholipid interactions. The intracellular perfusion of individual neurons in culture, either from SC or DRG, with monospecific affinity-purified anti-annexin VI antibodies resulted in an increase in the magnitude of the K+ current and in an increase in the Ca2+ current in sensory neurons. Our results suggest that the endogenous annexin VI regulates the Ca2+ conductance, which indirectly modifies Ca(2+)-dependent ionic conductances in SC and DRG neurons.

Delta/Notch signaling promotes formation of zebrafish neural crest by repressing Neurogenin 1 function

Development ◽  
2002 ◽  
Vol 129 (11) ◽  
pp. 2639-2648 ◽  
Author(s):  
Robert A. Cornell ◽  
Judith S. Eisen
Keyword(s):  
Dorsal Root Ganglion ◽  
Neural Crest ◽  
Notch Signaling ◽  
Sensory Neurons ◽  
Dorsal Root ◽  
Cell Formation ◽  
Dorsal Root Ganglion Neurons ◽  
Primary Neurons ◽  
Different Types ◽  
Ganglion Neurons

In zebrafish, cells at the lateral edge of the neural plate become Rohon-Beard primary sensory neurons or neural crest. Delta/Notch signaling is required for neural crest formation. ngn1 is expressed in primary neurons; inhibiting Ngn1 activity prevents Rohon-Beard cell formation but not formation of other primary neurons. Reducing Ngn1 activity in embryos lacking Delta/Notch signaling restores neural crest formation, indicating Delta/Notch signaling inhibits neurogenesis without actively promoting neural crest. Ngn1 activity is also required for later development of dorsal root ganglion sensory neurons; however, Rohon-Beard neurons and dorsal root ganglion neurons are not necessarily derived from the same precursor cell. We propose that temporally distinct episodes of Ngn1 activity in the same precursor population specify these two different types of sensory neurons.

Interaction of opioids and membrane potential to modulate Ca2+ channels in rat dorsal root ganglion neurons

1995 ◽  
Vol 73 (5) ◽  
pp. 1793-1798 ◽  
Author(s):  
M. D. Womack ◽  
E. W. McCleskey
Keyword(s):  
Dorsal Root Ganglion ◽  
Sensory Neurons ◽  
Action Potentials ◽  
Dorsal Root ◽  
Dorsal Root Ganglion Neurons ◽  
High Threshold ◽  
Partial Recovery ◽  
Drg Neurons ◽  
Ganglion Neurons ◽  
Ca2 Channels

1. Using patch-clamp methods, we show that brief prepulses to very positive voltages increase (facilitate) the amplitude of current through Ca2+ channels during a subsequent test pulse in some, but not all, dorsal root ganglion (DRG) sensory neurons. The amplitude of this facilitated current generally increases when the Ca2+ channels are inhibited by activation of the mu-opioid receptor. 2. The facilitated current is blocked by omega-conotoxin GVIA, activates in the range of high-threshold Ca2+ channels, and inactivates at relatively negative holding voltages. Thus facilitated current passes through N-type Ca2+ channels, the same channels that are inhibited by opioids and control neurotransmitter release in sensory neurons. 3. Although maximal facilitation occurs only at unphysiologically high membrane potentials (above +100 mV), some facilitation is seen after prepulses to voltages reached during action potentials. After return to the holding potential, facilitation persists for hundreds of milliseconds, considerably longer than in other neurons. Brief trains of pulses designed to mimic action potentials caused small facilitation (19% of maximal) in a fraction (8 of 24) of opioid-inhibited neurons. 4. We conclude that 1) prepulses to extremely positive voltages can cause partial recovery of Ca2+ channels inhibited by opioids; and 2) small, but detectable, facilitation is also seen after physiological stimulation in some DRG neurons. Facilitation, largely considered a biophysical epiphenomenon because of the extreme voltages used to induce it, appears to be physiologically relevant during opioid inhibition of Ca2+ channels in DRG neurons.

scholarly journals Interferon γ Gene Expression in Sensory Neurons: Evidence for Autocrine Gene Regulation

1997 ◽  
Vol 186 (12) ◽  
pp. 2023-2031 ◽  
Author(s):  
Harald Neumann ◽  
Hannes Schmidt ◽  
Elke Wilharm ◽  
Lüder Behrens ◽  
Hartmut Wekerle
Keyword(s):  
Patch Clamp ◽  
Sensory Neurons ◽  
Nuclear Translocation ◽  
Interferon Γ ◽  
Dorsal Root Ganglion Neurons ◽  
Neuronal Membrane ◽  
Cultured Neurons ◽  
Ifn Γ ◽  
Patch Clamp Electrophysiology ◽  
Ganglion Neurons

We explored expression and possible function of interferon-γ (IFN-γ) in cultured fetal (E15) rat dorsal root ganglion neurons combining whole cell patch-clamp electrophysiology with single cell reverse transcriptase polymerase chain reaction and confocal laser immunocytochemistry. Morphologically, we located IFN-γ protein in the cytoplasm of the neurons in culture as well as in situ during peri- and postnatal development. Transcripts for classic IFN-γ and for its receptor were determined in probes of cytoplasm sampled from individual cultured neurons, which had been identified by patch clamp electrophysiology. In addition, the cultured neurons expressed both chains of the IFN-γ receptor. Locally produced IFN-γ acts back on its cellular source. Phosphorylation and nuclear translocation of the IFN-inducible transcriptional factor STAT1 as well as IFN-γ–dependent expression of major histocompatibility complex class I molecules on the neuronal membrane were noted in untreated cultures. However, both processes were substantially blocked in the presence of antibodies neutralizing IFN-γ. Our findings indicate a role of IFN-γ in autocrine regulation of sensory neurons.

A Novel Ca2+ Influx Pathway in Mammalian Primary Sensory Neurons Is Activated by Caffeine

2001 ◽  
Vol 86 (1) ◽  
pp. 190-196 ◽  
Author(s):  
Robert E. Hoesch ◽  
Daniel Weinreich ◽  
Joseph P. Y. Kao
Keyword(s):  
Sensory Neurons ◽  
Ryanodine Receptors ◽  
Reversal Potential ◽  
Significant Rise ◽  
Adult Rabbit ◽  
Pharmacological Agents ◽  
Inward Current ◽  
Whole Cell Patch Clamp ◽  
Intracellular Ca ◽  
Ganglion Neurons

Single-cell microfluorimetry and electrophysiology techniques were used to identify and characterize a novel Ca2+ influx pathway in adult rabbit vagal sensory neurons. Acutely dissociated nodose ganglion neurons (NGNs) exhibit robust Ca2+-induced Ca2+ release (CICR) that can be triggered by 10 mM caffeine, the classic agonist of CICR. A caffeine-induced increase in cytosolic-free Ca2+ concentration ([Ca2+]i) is considered diagnostic evidence of the existence of CICR. However, when CICR was disabled through depletion of intracellular Ca2+stores or pharmacological blockade of intracellular Ca2+ release channels (ryanodine receptors), caffeine still elicited a significant rise in [Ca2+]i in ∼50% of NGNs. The same response was not elicited by pharmacological agents that elevate cyclic nucleotide concentrations. Moreover, extracellular Ca2+ was obligatory for such caffeine-induced [Ca2+]i rises in this population of NGNs, suggesting that Ca2+ influx is responsible for this rise. Simultaneous microfluorimetry with whole cell patch-clamp studies showed that caffeine activates an inward current that temporally parallels the rise in [Ca2+]i. The inward current had a reversal potential of +8.1 ± 6.1 (SE) mV ( n = 4), a mean peak amplitude of −126 ± 24 pA ( n = 4) at E m = −50 mV, and a slope conductance of 1.43 ± 0.79 nS ( n= 4). Estimated EC50 values for caffeine-induced CICR and for caffeine-activated current were 1.5 and ∼0.6 mM, respectively. These results indicate that caffeine-induced rises in [Ca2+]i, in the presence of extracellular Ca2+, can no longer be interpreted as unequivocal diagnostic evidence for CICR in neurons. These results also indicate that sensory neurons possess a novel Ca2+ influx pathway.

scholarly journals Internalization of lectins in neuronal GERL.

1977 ◽  
Vol 73 (1) ◽  
pp. 1-13 ◽  
Author(s):  
N K Gonatas ◽  
S U Kim ◽  
A Stieber ◽  
S Avrameas
Keyword(s):  
Plasma Membrane ◽  
Membrane Receptors ◽  
Dorsal Root Ganglion Neurons ◽  
Cytochemical Study ◽  
Receptor Complexes ◽  
Mouse Dorsal Root Ganglion ◽  
Respiration Inhibitors ◽  
Ricin Agglutinin ◽  
Plasma Membrane Receptors ◽  
Ganglion Neurons

Conjugates of ricin agglutinin and phytohemagglutinin with horseradish peroxidase (HRP) were used for a cytochemical study of internalization of their plasma membrane "receptors" in cultured isolated mouse dorsal root ganglion neurons. Labeling of cells with lectin-HRP was done at 4 degrees C, and internalization was performed at 37 degrees C in a culture medium free of lectin-HRP. 15-20 min after incubation at 37 degrees C, lectin-HRP receptor complexes were seen in vesicles or tubules located near the plasma membrane. After 1-3 h at 37 degrees C, lectin-HRP-receptor complexes accumulated in vesicles and tubules corresponding to acid phosphatase-rich vesicles and tubules (GERL) at the trans aspect of the Golgi apparatus. A few coated vesicles and probably some dense bodies contained HRP after 3-6 h of incubation at 37 degrees C. Soluble HRP was not endocytosed under the conditions of this experiment or when it was present in the incubation medium at 37 degrees C. Internalization of lectin-HRP-receptor conjugates was decreased or inhibited by mitochondrial respiration inhibitors but not by cytochalasin B or colchicine. These studies indicate that lectin-labeled plasma membrane moieties of neurons are endocytosed primarily in elements of GERL.

scholarly journals Effects of Anoxia and Aglycemia on Cytosolic Calcium Regulation in Rat Sensory Neurons

2008 ◽  
Vol 100 (1) ◽  
pp. 456-473 ◽  
Author(s):  
Michael Henrich ◽  
Keith J. Buckler
Keyword(s):  
Sensory Neurons ◽  
Cyclopiazonic Acid ◽  
Cytosolic Calcium ◽  
Neuronal Responses ◽  
Local Effects ◽  
Progressive Decline ◽  
Nociceptive Neurons ◽  
Plasmic Reticulum ◽  
Carbonyl Cyanide ◽  
Neuron Function

Nociceptive neurons play an important role in ischemia by sensing and transmitting information to the CNS and by secreting peptides and nitric oxide, which can have local effects. While these responses are probably primarily mediated by acid sensing channels, other events occurring in ischemia may also influence neuron function. In this study, we have investigated the effects of anoxia and anoxic aglycemia on Ca2+ regulation in sensory neurons from rat dorsal root ganglia. Anoxia increased [Ca2+]i by evoking Ca2+ release from two distinct internal stores one sensitive to carbonyl cyanide p-(trifluoromethoxy) phenylhydrazone (FCCP) and one sensitive to caffeine, cyclopiazonic acid (CPA), and ryanodine [assumed to be the endoplasmic reticulum (ER)]. Anoxia also promoted progressive decline in ER Ca2+ content. Despite partially depolarizing mitochondria, anoxia had relatively little effect on mitochondrial Ca2+ uptake when neurons were depolarized but substantially delayed mitochondrial Ca2+ release and subsequent Ca2+ clearance from the cytosol on repolarization. Anoxia also reduced both sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA) activity and Ca2+ extrusion [probably via plasma membrane Ca2+-ATPase (PMCA)]. Thus anoxia has multiple effects on [Ca2+]i homeostasis in sensory neurons involving internal stores, mitochondrial buffering, and Ca2+ pumps. Under conditions of anoxic aglycemia, there was a biphasic and more profound elevation of [Ca2+]i, which was associated with complete ER Ca2+ store emptying and progressive, and eventually complete, inhibition of Ca2+ clearance by PMCA and SERCA. These data clearly show that loss of oxygen, and exhaustion of glycolytic substrates, can profoundly affect many aspects of cell Ca2+ regulation, and this may play an important role in modulating neuronal responses to ischemia.

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